More on Final Gearing

Every two or three weeks I ride down to Ensenada and stay overnite at Hostel Sauzal at 344 “L” Street in El Sauzal approximately 1 ½ miles south of the 100 kilometer sign.  For $15 you get a clean bed and one of Maria’s tasty breakfasts in the a.m. (011-52-646-17-46381). Besides doing some writing and enjoying the coastal view, I always have a wonderful evening seafood meal at my favorite restaurant, Mariscos Bahia Ensenada located in the tourist district on Riveroll (about 6 miles south of Hostel Sauzal and near the huge Mexican flag).

My most recent trip was routine. In the morning after a good night’s sleep and breakfast, I headed north for the border on Hwy 3 stopping in San Antonio de Las Minas for a second breakfast at Road Runner Café. After downing a tasty plate of huevos a la mexicana I resumed my trip northward.

Near the halfway point I passed through Testarazo and saw a parked 2002 XR250 Honda near the north edge of town. Since the rider was standing next to the bike I decided to stop and see if he had a problem. Turned out “Mark” was merely letting his bike’s recently rebuilt engine cool down. Mark was well aware that he had purchased the wrong bike for long trips in windy and mountainous conditions. Trouble is he had compounded the problems inherent in the hot running air cooled XR250 engine:

  1. He had geared the bike too high by installing a 45 tooth rear sprocket in place of the stock 48 tooth part.
  2. He had installed a poor quality engine oil for break-in.

Over-gearing single cylinder motorcycle engines and lubricating them with cheap oil are stupid ideas promoted by the Internet that just won’t go away. I advised Mark to install a top quality synthetic motorcycle oil like Maxima 4 as soon as possible, and to reinstall the stock 48T rear sprocket. The best advice I gave Mark was not to lug the little 250 single’s engine. Going up hills or into wind with 45 teeth he should find himself in 5th or 4th gear rather than 6th most of the time. Even with stock gearing he will be using 4th and 5th a lot in such conditions.

Mark’s experience in trying to make a road bike out of a small dirt bike had caused him to begin looking for a more appropriate road going single. Even if he settles on a liquid cooled mid-sized power plant, gearing is still a matter he must deal with if he continues two lane mountain riding.

Here at Top Gun/MMP, none of us is geared stock for our mountainous terrain. If, however, I was to make a run up the freeway to visit Kurt Grife near San Luis Obispo, I would first change my gearing back from 15/45 to 15/42 (stock DR650) to accommodate the generally flatter terrain and higher speeds. It’s all about maintaining crank momentum thus preventing detonation and other problems that go along with engine lugging.

Good luck Mark!